A Comparison Between Non-potential and Potential Models for the Ionosphere Electric Fields and Calculation of the Shielding Currents.

The standard models for calculating the electric currents in the ionosphere usually are based on the assumption that the electric field causing this current is a potential field. Recently we have considered the model for numerically simulating the ionospheric currents without assuming a potential electric field. The proposed model involves the non-potential electric field which is not only responsible partially for the ionospheric currents, but also induces the shielding electric currents in the Earth ground. The latter effect is because the non-potential electric fields are not electrostatic and hence can not be shielded with the simple redistribution of the electric charges. The typical pattern of the shielding currents is obtained. We compare the solutions obtained within the different models for given IMF conditions, using BATSRUS (ideal MHD code at the adaptive grid) with spherical blocks. The approach with taking the non-potential fields into account appears to be computationally less expensive and works as well than classical ionospheric potential solutions, such as those used in most MHD models.